While the scale of the HIV epidemic remains large, it has entered a promising new phase, marked by unprecedented progress and opportunities. In view of the need to rigorously test interventions to improve the uptake, implementation, and translation of recent scientific findings into standard of care (the know-do gap), as well as to evaluate the impact of bringing such interventions to scale, we propose to launch a new research training program focused on Global HIV Implementation Science. Implementation science is the scientific study of methods to promote integration of research findings and evidence-based interventions into health care policy and practice, thus improving the quality and effectiveness of health services. A key element of translational research, implementation science encompasses a broad range of skills, including epidemiology, biostatistics, health economics, decision science, and sociology. The goal of the proposed Training Program is to prepare well qualified individuals for careers as independently-funded researchers and for leadership in global HIV implementation research. We have assembled an outstanding group of diverse faculty from multiple schools, departments, and centers at Columbia University and abroad who have distinguished themselves in mentorship and are leading cutting edge implementation research addressing HIV prevention among key populations, linkage to and retention in care, prevention of mother to child transmission, and TB/HIV integration. The Training Program will encompass streamlined coursework based on an individualized training plan; weekly faculty-trainee seminars; tailored mentorship; research experience in a variety of domestic and international field settings; presentations; manuscript and grant preparation; research seminars and colloquia; and instruction in the responsible conduct of research. The Training Program will also include rigorous evaluation of the quality and effectiveness of the Training Program, to ensure that trainees achieve the competencies and skills necessary for success as future leaders in HIV implementation science research. The five-year program aims to support seven (three predoctoral and four postdoctoral) trainees at any one time. Among the postdoctoral trainees, a mix of trainees with PhD, DrPH, and MD degrees will be sought. Predoctoral trainees will be required to pursue a doctoral degree in Epidemiology. The period of support will be three years for predoctoral candidates and two years for postdoctoral candidates. With stellar faculty, a unique training environment, and unparalleled research opportunities in domestic and international field settings, we are well-poised to lead this novel effort and nurture new investigators trained in multidimensional, interdisciplinary approaches to advance scientific knowledge and demonstrate the impact of interventions.